The present invention is directed to a dental handpiece arrangement having a drive motor with a drive shaft and a grip piece containing a grip sleeve with a head housing having a chuck arrangement to hold a tool which is rotated by a drive train that is connected to the drive shaft of the drive motor and an illumination arrangement to provide light in the work area of the tool.
It has been known for a long time in dental technology to mount with a removable connection a handpiece part which essentially contains a head housing with a gripping sleeve connected and is referred to in the technical field as a "hand and angle piece", on a drive part containing a drive motor. The connection is designed so that in its emplaced condition, the hand and angle piece can be rotated relative to the drive part while retaining the drive shaft connection. The coupling and uncoupling occurs by means of a rapid coupling via a guide sleeve which surrounds the drive shaft of the drive part as disclosed in U.S. Pat. No. 3,604,960. The connecting parts of the rigid coupling have dimensions which are according to ISO standards.
The construction of such a handpiece arrangement has been retained even with the introduction of what is referred to as an incorporated spray arrangement, i.e., the guidance of a cooling agent such as air and water within the drive parts and within the hand and angle piece. The guidance of the agent within the drive part is between the stator and motor housing and the agent is delivered at the guide sleeve or pin for transfer to the grip piece through a fluid coupling arrangement which includes radially extending ports in either one of the guide pins or socket of the grip piece and the other of the guide pins and socket having annular channels with O-ring seals for receiving the discharge from the ports. Such an arrangement is disclosed in U.S. Pat. No. 4,007,529.
A handpiece arrangement that is suitable for conventional hand and angle pieces is also known and incorporates the light guidance. For example, a light is guided within the handpiece part as disclosed in U.S. Pat. No. 4,518,355 which claims priority from German Patent Application No. 32 15 219. In one of these known embodiments, the light generator, which is an incandescent lamp, is situated at the acceptance part rotatably held on the drive part. Here, the hand and angle piece contains a light guide which extends from the head housing up to the motor side end and this light guide is positioned opposite the lamp in a corresponding fashion in the coupled condition. Mechanical dog elements are provided between the hand and angle piece and the acceptance parts which bring the light generator and the corresponding end of the light guide into coincidence when the two parts are coupled together so that the two parts will rotate together. Accordingly, contacts comprising slip rings are provided between the acceptance parts and the drive parts to provide power to the incandescent bulb.
In other known embodiments, the light generator is situated in an acceptance part which is rotatably situated at the back end of the drive part.
A handpiece arrangement is also known from European Patent No. 00 34 237 wherein the light generator is situated outside of the handpiece arrangement, for example, in a supply unit. Light from this unit is then supplied to the handpiece by optical light guides in a supply hose and also is transmitted between the various parts of the handpiece by light guides. Given this arrangement, the hand and angle piece is torsionally connected to the drive part after it has been coupled thereto and rotatability here occurs between the drive part and the connection part of the supply line.
In addition to these conventional handpiece arrangements, a handpiece arrangement wherein the gripping sleeve normally remains on the drive part and only relative short treatment heads containing the head housing are coupled to the drive part in an easily releasable fashion have also become common in recent years. The gripping sleeve will have a sleeve extending over the drive part which contains the agent guidance, and the gripping sleeve itself is only removed from the drive part for sterilization purposes. The gripping sleeve and the treatment head are freely rotatable relative to the drive part but the sleeve extending over the motor is not and it is capable of being withdrawn from the drive part together with the gripping sleeve as disclosed in U.S. Pat. No. 4,251,212. This type of handpiece arrangement has not been disclosed with any illumination device, however, there is a desire to be able to offer such a motor-driven handpiece arrangement which incorporates an illumination arrangement with light guidance.
Various different types of disclosed structures for the arrangement of light illumination in a gripping sleeve is due to the fact that the customer, dependent on the equipment of his device, can necessarily only employ handpieces or, respectively, grip sleeve embodiments provided for one or another construction of the drives, i.e., conventional "hand and angle pieces" with or without lights can only be coupled to conventional drive parts. Handpieces, whose rotatability is provided at the guide sleeve and handpieces whose rotatability is provided in a back part of the drive part can hereby only be respectively coupled to drive parts which are designed to fit these particular types of structures.